A powerful earthquake struck central Japan on Friday, forcing a brief suspension of bullet train services, but no tsunami warning was issued, authorities said.

The 6.5 magnitude quake hit the central Ishikawa region at 1:42pm Hong Kong time at a depth of 12 kilometres, according to the Japan Meteorological Agency.

Shinkansen bullet trains were suspended between Nagano and Kanazawa, a popular tourist destination, but resumed less than two hours later, according to Japan Railway.

There were no confirmed reports of casualties or damage.

Friday is a public holiday in Japan, part of a run of days off known as "Golden Week", a time when many people travel for leisure or to visit family.

In the city of Suzu, the quake registered an upper six on the Japanese Shindo seismic scale, which goes up to a maximum of seven, meaning it could cause major landslides.

The United States Geological Survey put the magnitude at 6.2 and said it struck just off the coast, but Japan's Meteorological Agency placed the epicentre on land.

Earthquakes are common in Japan, which sits on the Pacific "Ring of Fire", an arc of intense seismic activity that stretches through Southeast Asia and across the Pacific basin. (AFP)